Damping Valve Mechanism

ABSTRACT

A damping valve device includes an actuator which carries out an axial displacing movement on a sliding sleeve. The sliding sleeve, along with a fixed valve carrier, forms a slide valve which has two flow directions. The slide sleeve is impinged with damping medium on a front side and on a rear side in an incident flow direction, and the front side of the slide sleeve and rear side of the slide sleeve are impinged hydraulically in parallel by damping medium during the incident flow.

PRIORITY CLAIM

This is a U.S. national stage of application No. PCT/EP2016/058535,filed on Apr. 18, 2016. Priority is claimed on the followingapplication: Country: Germany, Application No.: 10 2015 209 318.2,filed: May 21, 2015, the content of which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention is directed to a damping valve device having anactuator which carries out an axial displacing movement on a slidingsleeve which forms part of an adjustable valve.

BACKGROUND OF THE INVENTION

An adjustable vibration damper which is marketed for, inter alia,motorcycles is known from US 20140116825 A1. In a motorcycle, thepermissible overall length of the vibration damper is even moredifficult to achieve compared with a passenger vehicle. It has turnedout that an adjustable damping valve device having a conventional pistonvalve and, in addition, a parallel bypass opening as is shown in FIG. 13of US 2014/0116825 A1 is suitable for this specific application.

A coil which exerts an axial displacing force on an armature is arrangedin an actuator housing on the piston rod side. A sliding sleeve which,with a valve sleeve fixed in the actuator housing, forms a slide valveis fastened to the armature. A return spring which preloads the slidingsleeve in a defined initial position is also arranged in the actuatorhousing.

Flow can occur in two directions in the slide valve. It is easy torecognize that dynamic pressure forces caused by an incident flow viathe channel in the piston rod tenon exert an opening force on the slidevalve. While there is indeed a static pressure compensation because thesurface area impinged by pressure on the front side of the slidingsleeve is equal to that on the rear side of the sliding sleeve, thedynamic pressure force component in direction of the channel isappreciably greater than on the rear side of the sliding sleeve.

During an incident flow via the channels in the annular flange of thepiston rod tenon, only mutually compensating radial forces act on thesliding sleeve. Consequently, there are substantial dynamic pressureforce differences between the two incident flow directions. Thesedifferences in pressure force make it more difficult to configure, e.g.,the return springs for the sliding sleeve in order to achieve a requireddamping force characteristic.

It is thus an object of the present invention to provide a damping valvedevice in which dynamic pressure forces influencing the opening behaviorand closing behavior of the slide valve are minimized.

SUMMARY OF THE INVENTION

This object is met in that the front side of the slide sleeve and rearside of the slide sleeve are impinged hydraulically in parallel bydamping medium during an incident flow.

In contrast to the cited prior art in which the front side of the slidesleeve and rear side of the slide sleeve are impinged hydraulically inseries by damping medium, dynamic pressure forces are extensivelycompensated at the slide sleeve. Accordingly, the sliding sleeveexhibits a uniform operating behavior which can be easily controlledregardless of the incident flow direction.

In a further advantageous embodiment, it is provided that a returnspring which orientates the sliding sleeve in an initial positionengages outside of the front side and rear side. The advantage consistsin that a return spring, often constructed as helical compressionspring, which produces a flow resistance and consequently alsoinfluences the dynamic pressure ratios in the damping valve device isnow no longer in the flow path and consequently can also not exert anyinfluence.

According to an advantageous embodiment, the return spring is arrangedinside the sliding sleeve and exerts the restoring force on a base ofthe sliding sleeve. The sliding sleeve can have a simple cross sectionbecause no additional supporting surfaces are needed for the returnspring.

In this respect, it is provided that the return spring is preloadedbetween the base of the sliding sleeve and the valve carrier. The valvecarrier is a comparatively stable component part which can easilysupport the occurring forces.

In order to maintain the pressure equilibrium of the damping valveoverall, the sliding sleeve has at least one connection opening to apressure compensation space.

The return spring is preferably arranged in the pressure compensationspace and is accordingly optimally radially guided. Therefore, a lateralbuckling of the spring need no longer be a concern.

A further advantage consists in that the damping valve carrier has asealing sleeve portion on both sides of a valve cross section of theslide valve. Accordingly, additional separate seals which minimize leaksin the slide valve and which therefore keep the damping behaviorreproducible are no longer required.

Optionally, it can be provided that the valve carrier is axiallydisplaceably supported. The preloading of the return spring can beinfluenced via the displacing mechanism. As a result, the damping forcecharacteristic of the damping valve device can also be controlled.

In order that dynamic pressure forces can be redirected from an axialflow path into a radial flow path, and vice versa, the valve carrier hasa central channel to which at least one diagonally extending transferchannel is connected. Turbulence in the slide valve is minimized in thisway.

To facilitate an orientation-free mounting and installation position incircumferential direction, the valve carrier has a circumferentialcollection groove to which the at least one transfer channel isconnected.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described more fully referring to the followingfigures, In which:

FIG. 1 shows a section from a vibration damper; and

FIG. 2 shows a detail of the adjustable valve.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIGS. 1 and 2 combined show a section from a vibration damper 1 of aselected type of construction in the region of a damping valve device 3which is fixed to an axially moveable piston rod 5. The damping valvedevice 3 has a damping valve 7 constructed as piston valve, wherein anannular valve body 9 of the damping valve divides a cylinder 11 filledwith damping medium into a working chamber 13 on the piston rod side anda working chamber 15 remote of the piston rod.

The damping valve device 3 has a pot-shaped housing 17 in which anactuator 19 is arranged. The actuator 19 comprises, inter alia, a coil21 which exerts an axial displacing force on an armature 23. Whenexcited, the coil 21 generates a displacing movement in move-outdirection of the armature 23 out of the housing 17. The radial bearingsupport of the armature 23 is implemented in a back-iron 25 and in apole disk 27 in each instance via bearing sleeves 29; 31, respectively.Accordingly, a base 33 which closes the housing 17 in direction of thedamping valve 7 is to be regarded as independent from the actuator 19.The actuator 19 is sealed in direction of the coil 21 and a cableconnection 35.

The base 33 of housing 17 and a support piece 37 are formed in one pieceand accordingly provide the connection to the damping valve 7, which canbe constructed in any manner known from the art and of which only oneexemplary embodiment form is shown. Only restrictor channels 39 and theassociated valve disks 41 for a flow connection between the workingchamber 15 remote of the piston rod and the working chamber 13 on thepiston rod side can be seen in this sectional view. A comparableconfiguration exists for the opposite flow direction, wherein only thevalve disks 43 of the operative damping valve are shown.

A bypass channel 45 to the damping valve 7 is formed in the supportpiece 37. The bypass channel 45 is controlled by an adjustable valve 47which is arranged in the support piece 37. The adjustable valve 47 is aslide valve with a valve body 49 constructed as a sliding sleeve whichis guided on a valve carrier 51. A return spring 53 which preloads thesliding sleeve 49 against the armature 23 in an initial directionengages outside of a front side 55 and rear side 57 of the slidingsleeve 49.

The return spring 53 is arranged inside the sliding sleeve 49 and exertsthe restoring force on a base 59 of the sliding sleeve 49. The returnspring 53 is axially preloaded between the base 59 and an end face 61 ofthe valve carrier 51.

The valve carrier 51 is axially displaceably supported inside the bypasschannel 45. For this purpose, e.g., a threaded connection 63 is providedwith the support piece 37.

The valve carrier 51 has a central channel 65 which is formed by ablind-hole aperture which is oriented in direction of the bypass channel45. At least one diagonally extending transfer channel 67 is connectedin turn to the central channel 65 and is connected to a circumferentialcollection groove 69 of the valve carrier. The collection groove 69 ispreferably formed at an inclination to the main axis of the centralchannel 65 in extension of the transfer channel 67 in order to achieve arounded out deflection of the flow.

The connection between the valve body 49 and the armature 23 of theactuator 19 is configured as a simple plug-in connection. The plug-inconnection is to be conceived of as a floating bearing which is designedfor transmitting axial pressure forces. A radial gap provides forcompensation of axial offset between the adjustable valve 47 and thearmature 23.

The piston valve or damping valve 7 with its valve disks 41; 43 and theannular valve body 9 is fixed by a fastener 71 which engage in thebypass channel 45. The fastener 71 is formed as a hollow screw and makeuse of a threaded portion which is also provided for the valve carrier51. The inner diameter of the hollow screw 71 is greater than the innerdiameter of the valve carrier 51 so that, not shown, at the valvecarrier 51 is accessible by a tool even when the piston valve 7 isassembled.

During assembly, a housing 17 connected to the hollow piston rod 5 isoutfitted with the actuator 19 in a separate construction segment. Aninner seal 73 and outer seal 75 at an insulating washer 77 protect thecoil 21 and cable connections, not shown, against moisture.

During a stroke movement of the piston rod 5, damping medium isdisplaced into the restrictor channels 39 from the working chamber 15remote of the piston rod. However, damping medium is also conveyed intothe bypass channel 45. A valve cross section is adjusted at theadjustable valve 47 depending on the axial position of the slidingsleeve 49. When the coil 21 is highly excited, the actuator 19 exerts alarge displacing movement via the armature 23 and moves the slidingsleeve 49 against the force of the return spring 53. This releases alarge valve cross section, which tends to be connected with a smallerdamping force. The axially acting dynamic pressure forces are supportedby the valve carrier 51 which is fixed in the bypass channel 45. Thesliding sleeve 49 is acted upon from the inside only by radial forceswhich, however, are completely compensated.

Without excitation of the coil 21, the valve body 49 is moved by thereturn spring 63 into a maximum restriction position. The restrictionposition can mean complete closure or a small restriction cross section.The comparatively large damping force is then generated substantially bythe damping valve 7.

During a compression movement of the piston rod 5 into the piston rodside working chamber 13, the damping medium flows via radial channels 79in the support piece 37 into an annular space 81 which is boundedradially inwardly by the a lateral surface of the sliding sleeve 49 andby the front side 55 and rear side 57 of the sliding sleeve 49. In thisregard, the front side 55 and the rear side 57 are acted uponhydraulically in parallel by damping medium. At least one connectionopening 83 ensures that a pressure compensation space 85 of the slidingsleeve is likewise provided with damping medium. The return spring 53 isalso arranged in this pressure compensation space 85. The annular space81 can also be appreciably narrower radially so that the diameter of thesupport piece is not allowed to decrease.

When damping medium enters at least one restriction opening 87 which,together with a valve edge 89 of the collection groove 69, determinesthe valve cross section, the damping medium is prevented from leaking inan undefined manner by valve carrier portions 91; 93 on both sides ofthe valve cross section. Of course, these valve carrier portions 91; 93are also operative when the valve cross section is impinged by a flowfrom the bypass channel 45.

Thus, while there have shown and described and pointed out fundamentalnovel features of the invention as applied to a preferred embodimentthereof, it will be understood that various omissions and substitutionsand changes in the form and details of the devices illustrated, and intheir operation, may be made by those skilled in the art withoutdeparting from the spirit of the invention. For example, it is expresslyintended that all combinations of those elements and/or method stepswhich perform substantially the same function in substantially the sameway to achieve the same results are within the scope of the invention.Moreover, it should be recognized that structures and/or elements and/ormethod steps shown and/or described in connection with any disclosedform or embodiment of the invention may be incorporated in any otherdisclosed or described or suggested form or embodiment as a generalmatter of design choice. It is the intention, therefore, to be limitedonly as indicated by the scope of the claims appended hereto.

1-10. (canceled)
 11. A damping valve device comprising: an actuator; afixed valve carrier and a sliding sleeve forming an adjustable valvehaving two flow directions; said actuator constructed for carrying outan axial displacement movement on said sliding sleeve; said slidingsleeve comprising a front side and a rear side impinged with dampingfluid in an incident flow direction, and wherein, during the incidentflow, said front side of said sliding sleeve and said rear side of saidsliding sleeve are impinged in parallel by the damping fluid.
 12. Thedamping valve device according to claim 11, additionally comprising areturn spring engaged outside of said front side and said rear side fororienting said sliding sleeve into an initial position.
 13. The dampingvalve device according to claim 12, wherein said sliding sleevecomprises a base, and wherein said return spring is arranged inside saidsliding sleeve and exerts a restoring force on said base of said slidingsleeve.
 14. The damping valve device according to claim 13, wherein saidreturn spring is preloaded between said base of the sliding sleeve andsaid valve carrier.
 15. The damping valve device according to claim 11,wherein the sliding sleeve comprises a pressure compensation space andat least one connection opening to said pressure compensation space. 16.The damping valve device according to claim 15, wherein said returnspring is arranged in said pressure compensation space.
 17. The dampingvalve device according to claim 11, wherein said valve carrier includesa valve carrier portion (91; 93) on both sides of a valve cross sectionof said sliding sleeve.
 18. The damping valve device according to claim11, wherein said valve carrier is axially displaceably supported. 19.The damping valve device according to claim 11, wherein said valvecarrier comprises at least one diagonally extending transfer channel,and wherein said valve carrier comprises a central channel to which saidat least one diagonally extending transfer channel is connected.
 20. Thedamping valve device according to claim 19, wherein said valve carriercomprises a circumferential collection groove to which said at least onetransfer channel is connected.